New technologies have been applied to solve problems created by a bandwidth hungry communications applications. One of the new technologies is the Asymmetric Digital Subscriber Line (ADSL). ADSL has promised high downstream rates to support services such as high speed Internet data access, video and audio streaming. While ADSL can be implemented in several different forms, in one form Frequency Division Multiplexed (FDM) systems provide bandwidth for both upstream and downstream flow. Desirably, the upstream rates are much lower as compared to the downstream rates. Typically the upstream spectrum for ADSL is placed lower in the frequency band as compared to the downstream spectrum.
For normal loops, loops which are considered short to medium in length, it is possible to achieve the high downstream rates. However using FDM systems implementing ADSL for long and severely impaired loops, that is loops impaired with cross talk and reasonably high noise floors, the modems may either fail to connect or if they synchronize, the downstream data rates are much lower than the upstream rates. This of course is not what ADSL is designed to provide. Particularly, the goal is to have downstream data rates larger, and perhaps much larger, than upstream data rates.